update user presence on a shared tab

When you are Presenting a Tab:
- there should be a Growl notification "You are presenting this tab to [user]"
- the browser tab should have a Presenting icon, color (green?) and maybe avatars of the people on the page are in the tab.
- the content window should have a light green outline too?

When you are Spectating on a Tab:
- there should be a Growl notification "You spectating on this tab by [user]"
- the browser tab should have a Spectating icon, color (blue?) and maybe avatars of the people on the page are in the tab.
- the content window should have a light blue outline too?

When are on a Shared Tab with another user:
- there should be a Growl notification "You are live-sharing on this tab with [user]"
- the browser tab should have a Share icon, color (?) and maybe avatars of the people on the page are in the tab.

When a user joins your tab you are Presenting on:
- there should be a Growl notification "[user] is spectating on your page."
- the browser tab should have a Presenting icon, color (green?) and maybe avatars of the people on the page are in the tab.
- the content window should have a light green outline too?

When a user joins a tab you are Spectating on:
- there should be a Growl notification "[user] is now spectating on this page too."
- the browser tab should have a Spectating icon, color (blue?) and maybe avatars of the people on the page are in the tab.
- the content window should have a light blue outline too?

When a user joins a page you are Sharing on:
- there should be a Growl notification "[user] has joined this page with you."
- the browser tab should have a Share icon, color (?) and maybe avatars of the people on the page are in the tab.